2. Moving from Analysis to Design
Analysis Phase
• Understand
events and
business
processes
• System
activities and
processing
requirements
• Information
Storage
Requirements
Analysis Models
and Documents
• System Scope
Document
• Gantt Chart
• Interview
Questionnaires
• Workflow
• Forms/Manuals
• ER Diagram
Design Phase
• Define,
organize, and
structure the
components of
the final
solution system
that will serve
as the blueprint
for construction
3. Design Phase Activities
Design and
Integrate
network
Design the
application
architecture
Design the
user
interfaces
Design the
System
Interfaces
Design and
integrate
the
database
Design and
integrate
system
controls
4. Design Phase Activities
Activity Key Question
Design and Integrate the network Have we specified how the various parts
of the system will communicate with each
other throughout the organization?
Design the Application Architecture Have we specified how each system
activity is actually carried out by the
people or computers?
Design the User Interfaces Have we specified how the users will
interact with the system?
Design the System Interfaces Have we specified how the system will
work with all other systems inside and
outside the organization?
5. Design Phase Activities
Activity Key Question
Design and Integrate the Database Have we specified how and where the
system will store all the information
needed by the organization?
Prototype for Design Details Have we created prototypes to ensure all
detailed design decisions have been fully
understood?
Design and integrate system controls Have we specified how we can be sure
that the system operates correctly and
the data maintained by the system are
safe and secure?
6. Design and Integrate a Network
• Computer Network
– A set of transmission lines, equipments and
communication protocols to permit sharing of
information and resources
– LAN, WAN, router, Internet, WWW, Intranet,
Extranet, Virtual Organization, VPN
7. Design the Application Architecture
• Client/Server Architecture
– Client – a process, module, object, or computer that
requests services from one or more servers
– Server – a process, module, object or computer that
provides services over a network
Client
Database
Server
Response
or Status
Code
8. Design the Application Architecture
• Three-Layer Client/Server Architecture
– A client/server architecture that divides the
application into the view layer, the business logic
layer and data layer
• View layer – the part that contains the user interface
• Business Logic Layer – the part that contains the
programs that implement the business rules of the
application
• Data Layer – the part that interacts with the database
9. Design the Application Architecture
• Three-Layer Client/Server Architecture
View Layer
Business
Logic Layer
Data
Layer
10. Design the Application Architecture
• The System Flowchart
– This is the representation of various computer
programs , files, databases, and associated manual
procedures that make up a complete system.
– It graphically describes the organization of the
subsystems into automated and manual
components.
11. Common System Flowchart Symbols
Process/
Program
File/
Database
Doc or
Report
IO
Screen
Display
File/
Database
Manual
Operation
Connection
12. The Structure Chart
• Structure Chart
– A hierarchical diagram that shows the
relationships between modules of a computer
program
13. The Structure Chart
Payroll
Program
Enter Time
Cards
Enter
Employee
Time card
Read
Employee
Time Card
Validate Time
Card
Calculate
Amounts
Get Employee
Pay Rates
Calculate Pay
Amounts
Calculate base
amount
Calculate
overtime
amount
Calculate
taxes
Calculate
other
deductions
Output
Payroll
Update
Employees
Record
Write payroll
transactions
Update
general
Ledger
14. Designing the Databases
• Database
– An integrated collection of stored data that is
centrally managed and controlled
• DBMS
– A system software that manages and controls the
database
• Schema
– A description of the structure, content and access
controls of a database
15. Designing the Databases
• Relational DBMS
– A database management system that stores data in tables
– Table
• A 2D data structure containing rows and columns (relation)
– Row
• A portion of the table containing data that describes one entity (record)
– Field
• A column of relational database table (attribute)
– Field Value
• Data value stored in a single cell of a relational database table
– Key
• A field that contains a value that is unique within each row of a table
– Primary Key
• A key used to uniquely identify a row of a database table
16. Designing the Database
• Represent entities using the ERD
• Create the database schema from an ERD:
– Create table for each entity type
– Choose a primary key for each table
– Add foreign keys to represent one-to-many relationships
– Create new tables to represent many-to-many
relationships
– Define referential integrity constraints
– Evaluate schema quality and make necessary
improvements
– Choose appropriate data types and value restrictions
17. Design the System/User Interface
• System Interface
– The parts of an information system involving
inputs and outputs that require minimal human
intervention
• User Interface
– The parts of an information System requiring user
interaction to create inputs and outputs
18. Understanding the User Interface
• Human-Computer-Interaction
– The study of end-users and their interactions with
computers
• Aspects of the User Interface
– Physical Aspect (keyboard, mouse, screen, etc.)
– Perceptual Aspect (data and instructions on the
screen)
– Conceptual Aspects (includes everything that the user
knows about the system)
• Remember: To the user, the user interface IS the
system itself
19. Guidelines for Designing the UI
• Interface Design Standards
– General principles and rules that must be followed for
the interface of any system developed by the
organization
• Visibility
– A key principle of HCI that states all controls should be
visible and provide feedback to indicate that the
control is responding to the user’s action
• Affordance
– A key principle of HCI that states the appearance of
any control should suggest its functionality
20. Eight Golden Rules for
Designing Interactive Interfaces
1. Strive for consistency
2. Enable frequent users to use shortcuts
3. Offer informative feedback
4. Design dialogs to yield closure
5. Offer simple error-handling
6. Permit easy reversal actions
7. Support Internal Locus of Control
8. Reduce Short-Term Memory Load
